Apparatus for marking insulated cables

ABSTRACT

A band marking apparatus for cables includes an annular nozzle which is normally closed and is opened by the marking material under a predetermined pressure. A proportioning valve operated by the moving cable controls the material applied to the nozzle. The nozzle includes two spring-like plates which open under pressure. The valve may include a rotary sliding element providing a pressurized seal or a solenoid valve controlled by a commutator driven by the cable. The nozzle plates may also be held closed by electromagnetic force.

United States Patent Kramer 1 1 Jan. 7, 1975 [54] APPARATUS FOR MARKING INSULATED 3,136,649 6/1964 Keahey, Jr. 118/8 X CABLES FOREIGN PATENTS OR APPLICATIONS [75] Inventor: Gert Kramer, Stuttgart, Germany 1,118,844 12/1961 Germany 118/D1G. 21 Assigneez International standard Electrical 1,031,851 6/1958 Germany 118/325 Corp" New York Primary Examiner-John P. McIntosh [22] Filed: Jan. 24, 1973 Attorney, Agent, or Firm-John T. OHalloran; [211 pp NOJ 326,216 Menottl J. Lombardi, Jr.; Edward Goldberg [57] ABSTRACT g" pp ly Data A band marking apparatus for cables includes an an- Feb. 25, 1972 Germany 2209027 nular nozzle which is normally closed and is opened by the marking material under a predetermined pres- [52] US. Cl 118/8, 118/325, 118/D1G. 21 sure. A proportioning valve operated by the moving [51] Int. Cl. B05c 5/00 cable controls the material applied to the nozzle. The [58] Field of Search 118/325, DIG. 21, 316, nozzle includes two spring-like plates which open 118/8, DIG. 18; 239/534, 535, 559, 567; under pressure. The valve may include a rotary sliding 117/43; 134/199 element providing a pressurized seal or a solenoid valve controlled by a commutator driven by the cable. [56] References Cited v The nozzle plates may also be held closed by electro- UNITED STATES PATENTS magnetic force- 2,533,191 12/1950 Jaeger 239/534 X 5 Claims, 7 Drawing Figures 4 Sheets-Sheet 1 Fig.7

Patented Jan. 7, 1975 3,858,544

4 Sheets-Sheet 2 Patented Jan. 7, 1975 3,858,544

4 Sheets-Sheet 5 my 5\ I 2% H g 1 i -4v I l-Hfi Patented Jan. 7, 1975 4 Sheets-Sheet 4 Fig.5

APPARATUS FOR MARKING INSULATED CABLES BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the continuous marking of extruded strands, such as insulated electric cable lines, by spraying colored band marks onto the preferably still hot soft surface of the insulation.

2. Description of the Prior Art Of many known apparatus suitable for marking cables, a particular German Pat. No. 1,031,851 is of interest in this connection. It has an annular-clearance nozzle which surrounds the moving cable and sprays a stream of color material onto the cable at short time intervals. An excess pressure periodically acts on the fluid color material. The apparatus consists of an annular nozzle, a color material tank, and a pressure capsule which is connected to the nozzle and filled with color material. As a result of a periodically activated diaphragm, an excess pressure communicates with the contents of the nozzle whereby annular color streams directed onto the line are produced for short periods of time.

In the above reference describing the known apparatus, the nozzle has anannular clearance which is always open. Sharply defined colored band marks can be proopening of the nozzle being constantly open. This con stantly open annular nozzle does not insure that the color material contained in the nozzle avoids the affect of the atmosphere. In addition, the width of the opening or clearance space of the known annular nozzle must be greater than 0.1 mm because the annular opening tends to clog due to the pigment particle size and the affect of the atmosphere. However, a width of the annular opening greater than 0.1 mm has the disadvantage of tending to drip, which constantly adversely effects the nozzles action.

Another disadvantage of the known apparatus is also attributed to the width of the annular opening. Since the amount of color material per color band to be produced is constant, the spraying time must decrease as the width of the clearance space increases. At an orifice diameter of the nozzle of 2 mm, a clearance width of 0.1 mm, and a color pressure of 4 kgf/cm the spraying time is about l/l0,000 seconds. These short pulse times are not realizable with the cam control described in connection with the known apparatus.

SUMMARY OF THE INVENTION It is therefore the object of the present invention to provide an apparatus for marking extruded strands which, while requiring a minimum of mechanical and- /or electrical equipment, permits improved reliable operation. The apparatus is relatively inexpensive, requires little maintenance and has short set-up times. In addition, no excess color material emerges from the apparatus during operation and the color material does not come into contact with the atmosphere, so that no clogging due to evaporation of the solvent can take place. Finally, the apparatus is to be self-purifying in respect of any small amounts of residual color material and safely permit very short spraying times.

The novel apparatus includes an annular nozzle which opens automatically under a predetermined internal pressure and is connected, via a pipe, with a color-material tank which is under constant pressure. A color-material-proportioning device is operated and/or controlled by the longitudinally moving extruded strand and is positioned in the pipe. In one embodiment of the invention, the annular nozzle consists of two spring-like plate elements forming a nozzle chamber. In another embodiment, the color-material-proportioning device is a rotary slide valve which consists of a housing with one inlet and at least one outlet and of a rotatably mounted, prestressed sliding element disposed in the housing. The sliding element is connected, via an axle. with a drive pulley driven by the extruded strand.

In a further embodiment, the color-materialproportioning device is a solenoid valve controlled by an electrical pulse generator. The electrical pulse generator consists of a commutator which is coupled with the drive pulley driven by the extruded strand. Two or more of the segments distributed over the circumference of the commutator are short-circuited and connected to brushes which are switched into the electrical circuit of the solenoid valve. In another embodiment, the annular nozzle may be controlled by an electromag net.

BRIEF DESCRIPTION OF THE DRAWINGS Further details of the invention will be apparent from the accompanying drawings, in which:

FIG. 1 schematically shows one embodiment of the novel apparatus; I

FIG. 2 schematically shows another embodiment including a solenoid valve controlled by a commutator pulse generator; I

FIG. 3a schematically shows one embodiment of the annular nozzle in cross-section with the nozzle chamber closed;

FIG. 3b is a side view of the nozzle; v

FIG. 3c is a sectional view of the nozzle chamber open;

FIG. 4 schematically shows the rotary slide valve serving as the color-material-proportioning device; and

FIG. 5 schematically shows the annular nozzle controlled by an electromagnet.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, the novel marking apparatus includes the extruded strand 1 to be marked, which is drawn through the center of the annular nozzle 3 in the direction of arrow 2. The annular nozzle is connected with the rotary slide valve 5, serving as the color-material-proportioning device, through a pipe 4. The sliding part of the rotary slide valve 5 is coupled with a drive pulley 6 driven by the extruded strand. The rotary slide valve 5 is connected, via another pipe 7, with a tank 9 filled at least partly with color material 8. Pressure is exerted on the color material in the tank by a gas, such as compressed air, which is under a considerably higher pressure than that of the atmosphere. The gas is fed into the tank via pipe 10 and a pressure relief valve 11 from another source (not shown). By adjustment of the pressure in the color-material tank, the quality of the color bands produced by the annular nozzle can be adapted to the running speed of the extruded strand, the viscosity of the color material, and to the desired thickness of the layer of the color band. Since the color material in the tank is kept under pressure during stoppage times as well, any evaporation of the color-material solvent is prevented.

FIG. 2 shows an apparatus similar to that of FIG. 1 with the corresponding components being designated by the same reference numerals. In this embodiment, the color-material-proportioning device is a solenoid valve 12 controlled by an electrical pulse generator. The pulse generator is a commutator which is coupled with the drive pulley 6. Some of the commutator segments 13 are short-circuited by means of conductive connections 14. Arranged on the commutator segments are brushes 15, which are in the circuit feeding the solenoid electromagnet. In this manner, the solenoid valve is controlled synchronously with the running speed of the extruded strand, so that, irrespective of the speed of the strand, the band marks can be produced thereon at the desired regular intervals.

FIGS. 3a to Sc show the novel annular nozzle 3, which consists of two spring-like plate elements 16 which enclose a ring-shaped nozzle chamber 17 always filled with color material. Because of the inherent mechanical tension of the plate elements, the annular nozzle aperture 18 is always closed when the pressure of the color material in the nozzle chamber 17 does not exceed a predetermined pressure. When this pressure is exceeded, the spring-like plates 16 are forced apart and the nozzle aperture 18 opens (FIG. 3c), allowing the color material to discharge at a speed in accordance with the pressure. When the pressure decreases, the plates immediately close again automatically, so that any dripping and drying-up of the color material in the nozzle chamber 17 and at the nozzle aperture 18 is avoided even if a stoppage lasts a protracted period of time. When the nozzle aperture is open, a highly concentrated stream of color mist is sprayed onto the extruded strand 1, so that a sharply defined colored band 19 (FIG. 3c) is obtained. Any traces of color material remaining at and drying onto the nozzle aperture are swept along due to the high material pressure when the nozzle aperture is reopened, so that the annular nozzle is also self-cleaning.

FIG. 4 shows the rotary slide valve 5, which, in one embodiment of the invention, serves as the color-material-proportioning device and consists of the housing 20 and the sliding element 21. The housing 20 is provided with an inlet 22 and several outlets 23 for the color material. As a result of the construction of the sliding element, the rotary slide valve is self-sealing since the more the pressure of the color material increases, the more th packing surfaces are pressed against each other. This action also automatically compensates for wear. The outlets 23 may also be equipped with valves, so that the desired number and density of the color bands per unit length of the extruded strands can be varied by closing or opening certain valves. In addition, a speed governor which stops the supply of color material when the extruded strand is at a standstill may be coupled with the drive pulley 6.

FIG. 5 shows another embodiment of the apparatus in which the annular nozzle 3, previously illustratd in FIG. 3, is controlled by an electromagnet. The latter consists of the coil 24, generating the magnetic flux, and the housing 25 of ferromagnetic material, which enclose the nozzle. The circumference of the annular nozzle is closed with a ring 26 of non-ferromagnetic material. The electromagnet, when energized, produces the force indicated by the arrows 27, which cause the spring-like plate elements of the annular nozzle to close due to electromagnetic action in addition to mechanical force. The combined mechanical and electromechanical force action should be greater than the color material pressure tending to open the plates. When the magnet is disconnected, the opening effect of the color material pressure prevails, and the nozzle aperture opens. Following excitation of the electromagnet, the nozzle aperture closes again. In this manner, the times during which the annular nozzle is open can be reduced even further.

.What is claimed is:

1. An apparatus'for marking a longitudinal strand comprising means feeding said strand in a longitudinal path, an annular nozzle having an annular chamber surrounding said strand for spraying marking material inwardly onto said strand moving through the center of said nozzle, the inner end of said chamber having a normally closed inwardly facing annular aperture which opens automatically under a predetermined internal material pressure, a container of marking material under a predetermined constant pressure, a pipe connected between said container and nozzle to apply said material under pressure to said nozzle, and a valve device coupled to the longitudinally moving strand and connected within said pipe to control said material applied to said nozzle and strand in accordance with the speed of movement of said strand.

2. The apparatus according to claim 1, wherein said annular chamber includes two facing engaging springlike plate elements maintaining said aperture in a normally closed position, said plates separating to open said aperture and permit said material to flow therethrough upon reaching said predetermined pressure.

3. The apparatus according to claim 2, wherein said valve device is a rotary slide valve including a housing having one inlet and at least one outlet and of a rotatably mounted sliding element disposed in the housing and pressed against the housing surfaces by the pressure of said material, and a drive pulley driven by the strand, said sliding element being rotatably coupled to said drive pulley.

4. The apparatus according to claim 2, wherein said valve device is a solenoid valve, and includes an electrical pulse generator for controlling said valve and a drive pulley driven by the strand and coupled to said pulse generator, said pulse generator including a commutator rotatably coupled to said drive pulley, said commutator having a plurality of short circuited segments distributed over the circumference, and brushes on the commutator electrically connecting said commutator to said solenoid valve.

5. An apparatus according to claim 2 including an electromagnet around said nozzle for maintaining saidd plate elements in a normally closed position. 

1. An apparatus for markIng a longitudinal strand comprising means feeding said strand in a longitudinal path, an annular nozzle having an annular chamber surrounding said strand for spraying marking material inwardly onto said strand moving through the center of said nozzle, the inner end of said chamber having a normally closed inwardly facing annular aperture which opens automatically under a predetermined internal material pressure, a container of marking material under a predetermined constant pressure, a pipe connected between said container and nozzle to apply said material under pressure to said nozzle, and a valve device coupled to the longitudinally moving strand and connected within said pipe to control said material applied to said nozzle and strand in accordance with the speed of movement of said strand.
 2. The apparatus according to claim 1, wherein said annular chamber includes two facing engaging spring-like plate elements maintaining said aperture in a normally closed position, said plates separating to open said aperture and permit said material to flow therethrough upon reaching said predetermined pressure.
 3. The apparatus according to claim 2, wherein said valve device is a rotary slide valve including a housing having one inlet and at least one outlet and of a rotatably mounted sliding element disposed in the housing and pressed against the housing surfaces by the pressure of said material, and a drive pulley driven by the strand, said sliding element being rotatably coupled to said drive pulley.
 4. The apparatus according to claim 2, wherein said valve device is a solenoid valve, and includes an electrical pulse generator for controlling said valve and a drive pulley driven by the strand and coupled to said pulse generator, said pulse generator including a commutator rotatably coupled to said drive pulley, said commutator having a plurality of short circuited segments distributed over the circumference, and brushes on the commutator electrically connecting said commutator to said solenoid valve.
 5. An apparatus according to claim 2 including an electromagnet around said nozzle for maintaining saidd plate elements in a normally closed position. 